1. Field of the Invention
The invention relates to switch gear having a front and a back, comprising at least one group of n power switches, n being an integer .gtoreq.2, each of which have their own input connection and their own output terminal and extend substantially in a longitudinal direction perpendicular to the front of the switch gear, at least one busbar compartment containing n busbars for each group of n power switches, which busbars extend parallel to said front, wherein each busbar compartment is enclosed by at least four walls, two of which are parallel to the front and two of which are perpendicular to the front, at least one group of n busbar disconnecters for each busbar compartment, for making and breaking contact between busbars and respective output terminals of the power switches, wherein the output terminals of the power switches are constructed as coupling elements, to each of which one linkage (24) is connected and a further linkage (24') can be connected in an opposing direction perpendicular to the longitudinal direction, wherein each linkage forms a connection between one of the power switches and one of the busbar disconnecters.
2. Description of the Related Art
Switch gear installations are in general use and are disclosed, for example, in German laid open application DE 28 20 927, in the name of Siemens AG, which describes switch gear provided with at least one partition and a boiler mounted in a recess in the partition, in which boiler a bushing circuit breaker is mounted which has at least one breaker arm, rotatable about an axis located between the two ends of the breaker arm. Switching elements located opposite one another and at least one ground switching element, positioned such that the switching elements can be connected to each other by the breaker arm or that the breaker arm can be connected to the ground switching element, are also present in the boiler. The said laid open application also discloses a further development having a second boiler with switching elements, as a result of which a switch gear installation is formed which is able to switch a three-phase busbar system with a three-phase feed cable. An embodiment is also shown in which two busbar systems with a feed cable can be switched. The disadvantage of the said installation is that the switch gear for a busbar system is not of modular construction and, therefore, expansion to a dual busbar system is not simple to implement and demands additional space. Because of the required modifications to an existing single busbar system, it is necessary for the entire installation to be shut down for the expansion in order to be able to work safely on the installation. Furthermore, the control elements are not all placed on one side of the installation, which has an adverse effect on the clarity of the layout and the accessibility of the installation.
Another switch gear installation is disclosed in German laid open application DE 33 30 550, in the name of Sprecher & Schuh AG, which shows an installation which comprises two busbar systems mounted in a casing, which busbar systems are connected to a branch via busbar disconnecters provided with integral ground switches. The branch consists of a power switch connected to a cable connector. The connection between the branch and the ground switches of the two busbar systems is made by two switch-over elements, which are rotatable about an axis. The switching elements can be connected to the power switch via a conductor or to a ground point. By this means it is possible to ground a busbar system, as a result of which work on the busbar system outside the switch gear can be carried out. A disadvantage is that for work on parts of a busbar system inside the switch gear, such as expansion of a single busbar system to a dual busbar system, the entire installation has to be shut down. The construction of the installation is such that the installation takes up an appreciable amount of space. Furthermore, because of the positioning of the various parts and control elements the clarity of the layout and the accessibility for work to be carried out is not optimum.
Switch gear of the type defined in the preamble is disclosed in European Patent EP-A 0 459 593 as switch gear for the low medium voltage range, also known as the modular medium voltage switching system (MMS) from Holec Holland. This installation is of the same type as that defined in the preamble, but is suitable only for applications up to 24 kV. The said installation comprises medium voltage switches (one for each phase) with coupling elements perpendicular thereto, to which coupling elements busbar disconnecters are connected which are able to make or break a connection to a busbar system. The MMS installation can be expanded in modular fashion (on the top or the bottom) with a second busbar system and associated busbar disconnecters.
Furthermore, the L-SEP switch gear from Elin Holec High Voltage BV, which has been designed for operation at 50 kV and above, is known as switch gear for the high voltage range. The L-SEP switch gear, as disclosed in EP-B 0 221 603, comprises a number of compartments filled with SF.sub.6 gas. With this switch gear the primary three-phase power is fed in or taken off at the rear in a so-called cable terminal compartment by means of cable connectors. The cable connectors are connected via dual make-and-break contact breakers (one per phase) to the high voltage switches (likewise one per phase) in a switch compartment that is located physically before the cable terminal compartment. The high voltage switches are operated by a drive mechanism that is located on the front of the switch gear. The high voltage switches are connected to busbar disconnecters (one per phase) with dual make-and-break elements. The said busbar disconnecters with dual make-and-break elements improve safety during maintenance work. 3-phase busbar systems run from the busbar disconnecters, horizontally and parallel to the front of the installation. Said busbar systems connect the various switch gear installations. In the L-SEP switch gear the busbar compartment is frequently of dual construction in order, for example, to be able to put a second busbar system into service if the first busbar system has to be taken out of service because of testing or maintenance work. The two busbar compartments are located physically above the switch compartment, the drive mechanisms for the busbar disconnecters being positioned on the top of the switch gear.
In the case of the L-SEP installation, as a consequence of the dimensions that are needed for the voltage to be switched by this installation, the controls for the power switches are located on the front of the switch gear and those for the busbar disconnecters on the top of the switch gear.